Infusion packet and its manufacture

ABSTRACT

The present invention relates to an infusion packet comprising a single sealed compartment ( 16 ), the compartment having a top ( 8 ) and a bottom ( 9 ) defined by two transverse seals ( 7 ) that are separated by a distance D, the distance D being in the range of 40 to 70 mm, wherein the compartment comprises at least one side gusset ( 15 ), the side gusset ( 15 ) consisting of two gusset panels ( 12 ) and three gusset creases ( 13, 14 ).

TECHNICAL FIELD OF THE INVENTION

The present invention relates to infusion packets, particularly infusion packets containing infusible material such as tea, and to apparatus and methods for producing such infusion packets.

BACKGROUND OF THE INVENTION

In the past, conventional infusion packets (e.g. tea bags) have typically been flat, comprising a single chamber filled with infusible material (e.g. leaf tea, herbal mixtures). More recently, double-chamber infusion packets such as those described in U.S. Pat. No. 2,593,608 (A.G.F. Rambold) have become popular. In such infusion packets, the infusible material is contained in two chambers, with each chamber being attached to the other at the base and apex. This type of infusion packet is thought to enable faster infusion by allowing an increased flow of water around the infusible material. However, a drawback of double-chamber infusion packets is that they require significantly more packet material than their single-chamber counterparts.

Thus there is a need for an infusion packet that has a similar infusion performance to a double-chamber infusion packet, but which requires less packet material.

SUMMARY OF THE INVENTION

In a first aspect the invention relates to an infusion packet comprising a single sealed compartment, the compartment having a top and a bottom defined by two transverse seals that are separated by a distance D, the transverse seals being at opposite ends of the compartment, the distance D being in the range of 40 to 70 mm, wherein the compartment comprises at least one side gusset, the side gusset consisting of two gusset panels and three gusset creases.

We have found that packaging infusible material in a single-chamber infusion packet comprising one or more side gussets allows the infusible material more room to move and/or improves the flow of water around the infusible material compared to a conventional single-chamber infusion packet. This enables faster infusion and/or produces an infusion with more flavour. It is additionally or alternatively envisaged that a gusseted single chamber infusion packet can contain less infusible material per packet and still achieve the same infusion performance as a conventional single chamber infusion packet.

The size of the infusion packet is such that it has outer dimensions that are similar to those of a conventional infusion packet. This means that the infusion packet can be conveniently used by consumers in the usual manner. Therefore, the distance D which separates the transverse seals is in the range of 40 to 70 mm, more preferably from 45 to 65 mm and most preferably from 50 to 60 mm.

It would be desirable to provide a single-chamber infusion packet with one or more gussets which can be formed and filled at a high rate of production.

Thus in a second aspect the invention relates to an apparatus for producing infusion packets, the apparatus comprising a longitudinal sealer for forming a web of packaging material into a tube and a means for drawing the tubular web past an outlet of a conduit, wherein the outlet of the conduit has an external cross-section comprising at least two vertices and wherein the apparatus comprises at least one forming member for indenting the tubular web between the vertices and additionally comprises sealing elements for compartmenting the tubular web at intervals along its length, wherein the sealing elements form transverse seals across the width of the indented tubular web and are adapted such that the distance D between successive transverse seals is in the range of 40 to 70 mm.

In a third aspect, the invention relates to a method of manufacturing an infusion packet from a web of packaging material comprising the steps of:

-   -   (a) sealing the web of packaging material to form a tubular web;     -   (b) drawing the tubular web along a conduit and past an outlet         of the conduit, wherein the conduit outlet has a cross-section         comprising at least two vertices;     -   (c) indenting a face of the tubular web between the vertices to         introduce creases into the packaging material, the creases         defining at least one gusset;     -   (d) forming a first transverse seal across the tubular web;     -   (e) delivering a dose of infusible material into the tubular web         via the conduit; and     -   (f) forming a second transverse seal across the tubular web,         wherein the first and second transverse seals define an         individual compartment that contains a dose of infusible         material, and wherein the first and second transverse seals are         formed such that they are separated by a distance D, the         distance D being in the range of 40 to 70 mm.

Tests and Definitions

As used herein the term “comprising” encompasses the terms “consisting essentially of” and “consisting of”. It should be noted that in specifying any range of values or amount, any particular upper value or amount can be associated with any particular lower value or amount. The disclosure of the invention as found herein is to be considered to cover all embodiments as found in the claims as being multiply dependent upon each other irrespective of the fact that claims may be found with multiple dependency or redundancy.

Infusible Material

As used herein the term “infusible material” refers to any infusible or soluble material which can be immersed in liquid to prepare an infusion. This process is referred to as brewing. The infusible material preferably comprises plant material. For example, infusible material may comprise plant material derived from Camellia sinensis, Aspalathus linearis, Mentha piperita, Matricaria recutita and/or mixtures thereof. In a preferred embodiment the infusible material comprises tea solids.

Tea Solids

As used herein the term “tea solids” refers to dry material extractable from the leaves of the plant Camellia sinensis var. sinensis and/or Camellia sinensis var. assamica. The leaves may have been subjected to a so-called “fermentation” step wherein they are oxidised by certain endogenous enzymes that are released during the early stages of “black tea” manufacture. This oxidation may even be supplemented by the action of exogenous enzymes such as oxidases, laccases and peroxidises. Alternatively the leaves may have been partially fermented (“oolong tea”) or may have remained substantially unfermented (“green tea”).

Liquid Permeable

As used herein the terms “liquid permeable” and “permeable to liquid” are used interchangeably to describe a water-insoluble, porous packaging material which has openings that permit liquids, especially aqueous liquids, to pass through. Suitable packaging materials include non-wovens, wet laid non-wovens and wovens made with polymers or cellulosic/polymer blends (e.g. cellulose or cellulose PP blends) or perforated films. The packaging material may be heat-sealable or non-heat-sealable. In certain embodiments, heat-sealable packaging material is preferred in order to facilitate a high rate of infusion packet production. In other embodiments, non-heat-sealable packaging material is preferred due to its biodegradability.

Determination of Infusion Characteristics

Consumer studies have shown that consumers use a wide range of methods to prepare infusions from infusion packets. For example, consumers have been observed to use “dynamic” infusion methods including stirring, dunking and squeezing the infusion packet in hot water. As an alternative to these methods, many consumers have been observed to use a “static” infusion method, i.e. allowing infusion for a set period with no agitation. In reality many consumers adopt a mixture of static and dynamic techniques e.g. they leave the infusion to brew and stir just prior to removal of the infusion packet or dunk the infusion packet for a few seconds before leaving the infusion to brew.

Mechanical “dynamic” and “static” procedures have been developed to allow infusion characteristics to be determined in a reproducible manner. These methods allow certain extraneous factors which are known to influence infusion performance (e.g. packet orientation, amplitude and speed of dunking, size of vessel, stirring rate etc.) to be controlled and so provide repeatable methods for comparing different infusion packet systems.

Dynamic Method

The dynamic (continuous dunking) procedure represents a laboratory simulation of consumer preparation of an infusion involving agitation of the infusion packet.

Apparatus

Infusion packet dunker with dunking arm (stroke length: 130 mm; stroke rate: 60 dunks per minute).

Spectrophotometer with continuous flow cell (5 mm path length).

Adapted beaker with drain tube at the bottom (400 mL capacity).

Peristaltic pump (60 mL/min flow rate.

Narrow bore tubing (˜1 to 3 mm I.D.).

Procedure

1. Connect the adapted beaker to the spectrophotometer using narrow bore tubing such that liquid leaves the beaker via the drain tube, travels via the peristaltic pump to the continuous flow cell and then returns to the beaker. The end of the tubing carrying the return flow from the spectrophotometer touches the side of the beaker above the surface of the liquid.

2. Set the spectrophotometer to measure absorbance at 445 nm and specify the total infusion time and the frequency of sampling (e.g. a total infusion time of 240 seconds with a sampling frequency of 1 sample per 5 seconds). Autozero with hot distilled water pumping through the cell.

3. Attach the infusion packet to the dunker with the dunking arm at its highest point (N.B. when the dunking arm is at its highest position the bottom of the infusion packet should be above the water level and when it is at its lowest point the infusion packet should be completely immersed).

4. Add 235 mL boiling water to the beaker and start the pump.

5. Briefly allow the system to stabilise, then start the dunker and the spectrophotometer.

6. At the end of the infusion time stop the spectrophotometer, the dunker and the pump.

7. Flush the apparatus with hot distilled water.

8. Repeat the procedure as necessary to obtain replicate data sets. A fresh infusion packet should be used each time. Preferably the procedure is repeated at least twice (giving results in triplicate).

Static Method

It is also possible to measure “static” infusion where the infusion packet is not dunked except to initially dip the infusion packet into the liquid at the start point. For the sake of convenience the same procedure and apparatus as described above can be used without the dunker in motion. Alternatively a clamp attached to a retort stand may be used to suspend the infusion packet. Preferably the procedure is repeated at least five times (giving results in sextuplicate). A fresh infusion packet should be used each time.

DETAILED DESCRIPTION

Certain embodiments of the invention are illustrated by the drawings, in which:

FIG. 1 is a view of a web of packaging material according to an embodiment of the invention;

FIG. 2 a is a perspective rear view of a partly completed packet according to an embodiment of the invention;

FIG. 2 b is a perspective front view of the partly completed packet of FIG. 2 a;

FIG. 2 c is a cross-sectional view of the partly completed package of FIG. 2 a viewed from above;

FIGS. 3 a to 3 e are a series of perspective front views showing steps in the formation of an infusion packet according to an embodiment of the invention;

FIG. 4 shows an illustration of an apparatus for producing infusion packets according to an embodiment of the invention; and

FIGS. 5 a and 5 b show cross-sectional views of two possible embodiments of the conduit outlet of the apparatus of FIG. 4 viewed from above.

FIG. 1 shows a view of a web of packaging material according to an embodiment of the invention in which an elongate web 1 of liquid-permeable packaging material is travelling in a direction Z. The web of packaging material has a width W. A length L corresponding to one packet is indicated by boundaries 2, but the web can be of indefinite length. A single infusion packet comprises a portion of the elongate web with side margins 3 along its edges, and end margins 4, 5 either side of the boundaries 2.

A single infusion packet consists of packaging material that covers an area A. The area A is a convenient measure of the amount of packaging material required to form each infusion packet. In order to minimise environmental impact, it is desirable to limit the amount of packaging material used to form each infusion packet. However, it is undesirable to restrict the amount of packaging material to such an extent that the infusion performance of the infusion packet is compromised. Therefore, in order to balance environmental impact and infusion performance, a single infusion packet according to the present invention preferably consists of packaging material that covers an area A of from 5000 to 10500 mm², more preferably from 5500 to 9000 mm² and most preferably from 6000 to 7500 mm².

In a preferred embodiment each infusion packet comprises a substantially rectangular portion of the elongate web, wherein the area A is equivalent to the packet length L multiplied by the web width W (i.e. A=L×W). From the standpoint of convenience, it is preferred that the infusion packet will fit in a cup and/or a mug. Therefore it is desirable that the length L is not too great. However, the infusion packet should also be large enough to contain sufficient infusible material to produce a flavourful beverage. Therefore, the packet length L is preferably from 44 to 80 mm, more preferably from 48 to 75 mm and most preferably from 52 to 70 mm. Preferably the web width W is from 90 to 160 mm, more preferably from 95 to 140 mm and most preferably from 100 to 125 mm.

A longitudinal seal 6 comprises the side margins 3 in a finished packet according to a preferred embodiment of the invention (see FIG. 2 c). In particularly preferred embodiments the longitudinal seal 6 may be a fin seal or a lap seal.

Transverse seals 7 define the top 8 and bottom 9 of a finished packet (see FIG. 3 d). The transverse seals comprise the end margins 4, 5 of the web of packaging material. In a preferred embodiment, the transverse seals 7 are formed such that they are parallel to one another and perpendicular to the longitudinal seal 6.

The packet has a front face and a rear face. In a preferred embodiment, the front face comprises a single front panel 10 and the rear face comprises two back panels 11.

At least one gusset is introduced comprising gusset panels 12 which are delimited by gusset creases formed along lines 13, 14. Preferably the gusset(s) extend substantially longitudinally between the transverse seals 7 that define the top 8 and bottom 9 of a finished packet.

The finished packet comprises at least one side gusset 15, and preferably has two side gussets 15. A side gusset 15 consists of two gusset panels 12 and three gusset creases (two outer creases 13 and one central crease 14). In a preferred embodiment, each side gusset 15 separates the front and back panels. In a particularly preferred embodiment, the width of each gusset panel 12 is no more than 15 mm, and the total width of each side gusset 15 (i.e. the distance between the two outer creases 14 when the gusset is fully extended) is no more than 30 mm. Preferably each gusset panel 12 has a width of 3 to 10 mm, more preferably 4 to 8 mm. Preferably the total width of each side gusset 15 is from 6 to 20 mm, more preferably from 8 to 16 mm.

FIGS. 2 a to 2 c show three different views of a partly completed packet after the formation of the longitudinal seal 6 and two side gussets 15, as per one of the preferred embodiments. FIG. 2 a shows a perspective view of the packet viewed from the rear, with the longitudinal seal 6 running down the rear face between the two back panels 11. FIG. 2 b shows a perspective view of the same packet viewed from the front. FIG. 2 c shows a cross-section of the partly completed packet viewed from above, showing a compartment 16 which is defined by a front face comprising a front panel 10, a rear face comprising two back panels 11 joined by a longitudinal seal 6, and two side gussets 15, with each side gusset 15 comprising two gusset panels 12. The side margins 3 (FIG. 1) are incorporated into the longitudinal seal 6, which in this embodiment is a fin seal. Each side gusset 15 is “M”-shaped, and consists of two gusset panels 12, two outer creases 13 and one central crease 14. An outer crease 13 defines the border between a gusset panel 12 and a front panel 10 or a back panel 11, while a central crease 14 defines the border between two gusset panels 12.

FIGS. 3 a to 3 e are a series of perspective views which illustrate a sequence of process steps that can be carried out to form an infusion packet as a continuous web 1 of liquid-permeable packaging material moves through successive operating stations. In a first station, the side margins 3 of the web are sealed together with a longitudinal seal 6 to give the web a tubular form (FIG. 3 a). In a second station, the tubular web is indented so as to introduce creases that define one or more gusset(s). For example, FIG. 3 b shows a preferred embodiment in which two “M”-shaped side gussets 15 have been introduced into the tubular web. The web travels vertically (downwards) to a sealing zone where the transverse seals 7 that define the individual packets are formed. A transverse seal is formed such that it defines the bottom 9 of the present packet above the seal and the top 8 of a preceding packet below the seal (FIG. 3 c). An input device delivers a dose of infusible material 17 into the tubular web and a further transverse seal 7 is formed such that it defines the top 8 of the present packet and the bottom 9 of a succeeding packet as shown in FIG. 3 d. Thus the tubular web is filled with doses of infusible material 17 as it is formed into a chain of packets defined by the transverse seals 7. The chain of packets is subsequently separated into individual packets by severing the web at the transverse seals 7 along the boundaries 2 as shown in FIG. 3 e. In an alternative embodiment, it is possible to seal and cut in a single operation rather than having these operations performed serially.

The infusion packets according to the present invention comprise a compartment 16 having a top 8 and a bottom 9 defined by two transverse seals 7 that are separated by a distance D, the seals being formed at opposite ends of the compartment 16. From a standpoint of convenience of use, an infusion packet according to the present invention is similar in size to that of a conventional infusion packet. Preferably the infusion packet will fit in a cup and/or a mug. Therefore, the distance D is from 40 to 70 mm, more preferably from 45 to 65 mm and most preferably from 50 to 60 mm. It is preferred that the infusion packet is able accommodate sufficient infusible material to produce a flavourful beverage. In certain preferred embodiments the infusion packet contains from 1.0 to 3.8 g of infusible material, more preferably from 1.3 to 3.4 g and most preferably from 1.6 to 3.0 g.

FIG. 4 illustrates a preferred embodiment of an apparatus for manufacturing infusion packets according to the present invention. This apparatus has a single production path being supplied with infusible material 17 by a doser (not shown). A web of packaging material 1 is fed over a shaping guide near the inlet 20 of a conduit 21. Preferably the conduit inlet 20 has a circular cross-section. Here the web takes up the tubular form of the conduit exterior and is drawn down the tube by one or more guide elements 22 while its opposite side margins are sealed together longitudinally by a longitudinal sealer 23. In a preferred embodiment, the longitudinal sealer 23 is adjacent to the conduit and in a particularly preferred embodiment the longitudinal sealer 23 comprises a pair of heating and pressing rollers that weld the side margins together to form a longitudinal fin seal.

The tubular web is drawn along the conduit 21 and past the outlet of the conduit 24, preferably by one or more guide elements 22.

The conduit outlet 24 has an internal cross-section and an external cross-section that can be the same shape (see FIG. 5 a) or different shapes (see FIG. 5 b). In particular, it is preferred that the conduit outlet 24 has an external cross-section comprising at least two vertices 25. In a preferred embodiment the conduit transitions from having a circular cross-section (both externally and internally) at its inlet to having an external cross-section at its outlet that comprises at least two vertices 25. More preferably the external cross-section of the conduit outlet comprises at least two vertices 25 that delimit a face, and in especially preferred embodiment, such as the ones illustrated in FIGS. 5 a and 5 b, the conduit outlet has a rectangular external cross-section. In order to maximise the flow of infusible material through the conduit, it is preferred that the internal cross-section of the conduit outlet is the same shape as the external cross-section, for example as illustrated in FIG. 5 a. It may be desirable to prevent accumulation of infusible material at the vertices of the internal cross-section of the conduit outlet. Therefore, in certain other embodiments, the internal cross-section of the conduit outlet may comprise fewer vertices than the external cross-section, for example as illustrated in FIG. 5 b.

The tubular web is indented between the vertices 25 by at least one forming member 26.

Preferably the forming member(s) 26 are situated adjacent to the conduit outlet 24. For example, FIGS. 4, 5 a and 5 b show preferred embodiments in which the tubular web is indented by two forming members 26, with each forming member introducing an “M”-shaped side gusset 15 (FIG. 2 illustrates a partially completed packet made using the apparatus illustrated in FIG. 4 following gusset formation but prior to compartmenting the tubular web).

In the preferred embodiment illustrated in FIG. 4, the indented web is drawn vertically (downwards) to a sealing zone, where the apparatus comprises transverse sealing elements for compartmenting the tubular web at intervals along its length. The transverse sealing elements form successive transverse seals 7 across the width of the indented tubular web. The progress of the tubular web 1, which is preferably progressing at a substantially uniform speed, and the timing of the sealing elements are adapted such that the distance D between successive transverse seals is in the range of 40 to 70 mm, more preferably from 45 to 65 mm and most preferably from 50 to 60 mm.

The indented tubular web is filled with doses of infusible material as it is formed into a chain of packets defined by the transverse seals 7. In a preferred embodiment, an input device delivers the infusible material via the conduit such that each sealed compartment comprises a single dose of infusible material. The compartmented tubular web is subsequently separated into individual packets by severing the web at the transverse seals 7. In the preferred embodiment illustrated in FIG. 4, the cutting elements are carried on a pair of rotors 27 wherein the rotors comprise recesses 28 which accommodate the filled infusion packets as they progress along the production path.

In a particularly preferred embodiment, the sealing elements are carried on first a pair of rotors and the cutting elements are carried on a second pair of rotors, wherein both the first and second pair of rotors comprise recesses 28 which accommodate the filled infusion packets as they progress along the production path.

In an alternative embodiment, it is possible to seal and cut in a single operation rather than having these operations performed serially. In such an embodiment, the sealing and cutting elements may preferably be carried on a single pair of rotors.

EXAMPLE

The infusion characteristics of a conventional double-chamber infusion packet (packet DC) and an infusion packet according to the present invention (packet G) were investigated using both the dynamic (continuous dunking) and static procedures as described above. The total infusion time was 240 seconds and the sampling frequency was 1 sample per 5 seconds. The results are presented in Table 1. The infusion performance for static infusion is the mean of triplicate data sets, whilst for dynamic infusion it is the mean of duplicate data sets.

Packet DC and packet G were similar in apparent size (i.e. both were approximately 40 mm by 60 mm when viewed from the front). Packet DC was made from filter material having an area A of approximately 14270 mm². Packet G had two side gussets and was made from filter material having an area A of approximately 7680 mm²; D was approximately 52 mm. All packets contained approximately 2 g of Lipton Yellow Label tea.

The results show that the infusion characteristics of packet G are comparable to packet DC.

TABLE 1 Infusion performance (Abs @ 445 nm) Time Static infusion Dynamic infusion (sec) Packet DC Packet G Packet DC Packet G 0 0.018 0.012 0.001 0.011 5 0.007 0.012 0.204 0.061 10 0.010 0.013 0.320 0.220 15 0.015 0.020 0.413 0.313 20 0.034 0.033 0.478 0.401 25 0.069 0.059 0.540 0.472 30 0.104 0.080 0.595 0.529 35 0.135 0.106 0.640 0.590 40 0.149 0.114 0.674 0.636 45 0.172 0.148 0.707 0.675 50 0.180 0.167 0.735 0.709 55 0.199 0.183 0.761 0.742 60 0.230 0.215 0.784 0.771 65 0.239 0.261 0.804 0.796 70 0.255 0.249 0.826 0.819 75 0.281 0.307 0.844 0.840 80 0.291 0.317 0.861 0.861 85 0.309 0.327 0.877 0.881 90 0.315 0.334 0.892 0.896 95 0.344 0.351 0.904 0.913 100 0.343 0.331 0.918 0.928 105 0.335 0.347 0.930 0.943 110 0.354 0.352 0.941 0.956 115 0.366 0.413 0.952 0.968 120 0.382 0.384 0.961 0.980 125 0.368 0.387 0.972 0.990 130 0.385 0.393 0.983 1.003 135 0.391 0.414 0.990 1.013 140 0.393 0.419 0.997 1.021 145 0.404 0.410 1.006 1.032 150 0.404 0.431 1.015 1.041 155 0.411 0.433 1.021 1.050 160 0.419 0.430 1.029 1.060 165 0.428 0.446 1.037 1.066 170 0.435 0.456 1.045 1.075 175 0.440 0.463 1.052 1.083 180 0.447 0.465 1.057 1.088 185 0.446 0.481 1.065 1.095 190 0.455 0.496 1.073 1.102 195 0.458 0.487 1.078 1.108 200 0.465 0.496 1.082 1.114 205 0.469 0.513 1.091 1.121 210 0.475 0.520 1.096 1.128 215 0.474 0.522 1.101 1.134 220 0.483 0.528 1.105 1.141 225 0.488 0.532 1.111 1.147 230 0.491 0.541 1.116 1.151 235 0.504 0.550 1.121 1.158 240 0.502 0.546 1.125 1.162 

1. An infusion packet comprising a single sealed compartment (16), the compartment having a top (8) and a bottom (9) defined by two transverse seals (7) that are separated by a distance D, the transverse seals being at opposite ends of the compartment, the distance D being in the range of 40 to 70 mm, wherein the compartment (16) comprises at least one side gusset (15), the side gusset (15) consisting of two gusset panels (12) and three gusset creases (13, 14), and wherein the infusion packet consists of liquid-permeable packaging material that covers an area A of from 5000 to 10500 mm².
 2. An infusion packet according to claim 1 wherein the compartment (16) has two side gussets (15) and wherein each side gusset (15) consisting of two gusset panels (12) and three gusset creases (13, 14).
 3. An infusion packet according to claim 1 wherein the transverse seals (7) defining the top (8) and bottom (9) of the compartment are substantially parallel to one another and the gusset creases (13, 14) are orientated such that they are substantially perpendicular to the transverse seals.
 4. An infusion packet according to claim 1 wherein the infusion packet consists of liquid-permeable packaging material that covers an area A of from 5500 to 9000 mm².
 5. An infusion packet according to claim 1 wherein the compartment encloses a dose of infusible material comprising tea solids.
 6. Apparatus for producing infusion packets, the apparatus comprising a longitudinal sealer (23) for forming a web of packaging material into a tube and a means for drawing the tubular web past an outlet (24) of a conduit (21), wherein the outlet of the conduit has an external cross-section comprising at least two vertices (25) and wherein the apparatus comprises at least one forming member (26) for indenting the tubular web between the vertices (25) and additionally comprises sealing elements for compartmenting the tubular web at intervals along its length, wherein the sealing elements form transverse seals (7) across the width of the indented tubular web and are adapted such that the distance D between successive transverse seals is in the range of 40 to 70 mm.
 7. Apparatus according to claim 6 wherein the at least two vertices (25) delimit a face.
 8. Apparatus according to claim 6 wherein the web of packaging material is drawn along the exterior of the conduit by a guide element (22).
 9. Apparatus according to claim 6 wherein the apparatus comprises a longitudinal sealer (23) adjacent to the conduit for forming the web of packaging material into a closed tube around the conduit.
 10. Apparatus according to claim 6 wherein the conduit has an inlet (20) and an outlet (24), the inlet (20) having a circular cross-section both externally and internally, and wherein the conduit transitions from having the circular cross-section at the inlet (20) to having an external cross-section comprising at least two vertices (25) at the outlet (24).
 11. Apparatus according to claim 6 wherein the apparatus comprises transverse sealing elements and cutting elements, preferably wherein the sealing and/or cutting elements are carried on at least one pair of rotors (27).
 12. A method of manufacturing an infusion packet from a web of liquid-permeable packaging material comprising the steps of: (a) sealing the web of packaging material to form a tubular web; (b) drawing the tubular web along a conduit (21) and past an outlet (24) of the conduit, wherein the conduit outlet has a cross-section comprising at least two vertices (25); indenting a face of the tubular web between the vertices (25) to introduce creases (13, 14) into the packaging material, the creases defining at least one gusset (15); (d) forming a first transverse seal (7) across the tubular web; (e) delivering a dose of infusible material (17) into the tubular web via the conduit; and (f) forming a second transverse seal (7) across the tubular web, wherein the first and second transverse seals define an individual compartment (16) that contains a dose of infusible material, (g) separating the compartments defined by the transverse seals into individual infusion packets by severing the web at the seals, wherein the first and second transverse seals are formed such that they are separated by a distance D, the distance D being in the range of 40 to 70 mm, and wherein the infusion packet consists of packaging material that covers an area A of from 5000 to 10500 mm².
 13. (canceled)
 14. A method according to claim 12 wherein the sealing and severing of the web are performed at separate stations.
 15. A method according to claim 12 wherein the tubular web is drawn along the conduit at a substantially uniform speed.
 16. (canceled) 